Dividing the earth into climates

This lesson asks you to describe the major climate regions of the world and the natural processes and other factors that create and change climate patterns. The museum offers a medieval way of dividing the earth into climates, from al-Masudi and al-Muqaddasi; it is not what modern climate maps show, so your class brings the modern climate regions and the evidence for them. ¹

Compare the factors the medieval authors name, such as the sun's rays and heat, with the ones your class uses. Ask which of their explanations rest on position or sun, and which would need new evidence today.

Al-Masudi notes that, according to the astronomers, each quarter of the earth, northern and southern, contains seven climates. Inhabited land extends twenty-four degrees beyond the equator, and the rest is covered by the great sea ². Habitation is impossible in places where the heat is excessive or the sun is too far, and there cold and ice prevail. The best inhabited land is the one on which the rays of the sun fall clear, which is the fourth climate; for this group it is Iraq ^{2 3}. The words "for this group" matter: the record reports a way of dividing the world that belongs to the astronomers, not a map of climate as the class will draw it.

The seven climates are a division of the inhabited earth according to the astronomers, as reported by al-Masudi. Al-Muqaddasi departed from it and divided the lands of Islam in another way ^{2 4}. He made the climates of Islam fourteen: six Arab ones and eight non-Arab ones, and he began each climate with its chief city, where the ruler resided and where the administrative offices were gathered ⁴.

The astronomers divided the earth by how the sun's rays fall, and al-Muqaddasi divided the lands of Islam by the chief city of each climate, where the ruler lived and the offices stood. What question does each way of dividing answer? Which would you use to plan a trade route, and why?

• The seven climates: the astronomers' division and al-Muqaddasi's fourteen.
• Al-Masudi: who reports the astronomers' division.
• Al-Muqaddasi: who divided the lands of Islam another way.

Read The seven climates. List each factor the authors give for a place's climate, then add the factors your class has learned.